A semiconductor optical element includes: a first conductivity type semiconductor substrate; and a laminated body disposed on the first conductivity type semiconductor substrate. The laminated body includes, in the following order from a side of the first conductivity type semiconductor substrate: a first conductivity type semiconductor layer; an active layer; a second conductivity type semiconductor layer; and a second conductivity type contact layer. The second conductivity type semiconductor layer includes: a carbon-doped semiconductor layer in which carbon is doped as a dopant in a compound semiconductor; and a group 2 element-doped semiconductor layer in which a group 2 element is doped as a dopant in a compound semiconductor. The carbon-doped semiconductor layer is disposed at a position closer to the active layer than the group 2 element-doped semiconductor layer.

Provided is a semiconductor laser diode. Although the materials used in the conventional technology can reduce the strain, the selections of materials are relatively limited and the carrier confinement ability is not good. To solve the above-mentioned problems, a phosphorus-containing semiconductor layer is provided in a laser diode. As such, it can effectively reduce the strain of the active region or the total strain of the laser diode, and improve the carrier confinement capability of the active region. Therefore, it can effectively reduce the total strain or significantly improve carrier confinement under appropriate conditions of the laser diode. In some cases, it has the aforesaid effects. The phosphorus-containing semiconductor layer is suitable for an active region with one or more active layers. Especially after the phosphorus-containing semiconductor layer is provided in the active region with multiple active layers, high temperature performance are significantly improved or enhanced.

The invention relates to a quantum cascade laser (300) comprising a gain region (102) inserted between two optical confinement layers (104.sub.1, 104.sub.2), said gain region (102) having an electron input into the gain region (102) and an electron output from said gain region (102) characterized in that said laser comprises a hole-blocking area (304) on the side of said electron output.

System and method for increasing VCSEL power by using multiple gain layers 10, separated by insulated layers 12, bounded on top and bottom by DBR mirrors 11, connected in parallel through electrodes embedded within, resulting in a modified VCSEL system of higher power, lower resistive loss, higher device speed, and higher beam quality.

A semiconductor laser element includes an n-side semiconductor layer, an active layer, and a p-side semiconductor layer. A least a portion of the p-side semiconductor layer forms a ridge projecting upward. The p-side semiconductor layer includes an undoped first part, an electron barrier layer containing a p-type impurity and having a larger band gap energy than the first part, and a second part having at least one p-type semiconductor layer. The first part includes an undoped p-side composition graded layer in which a band gap energy increases towards the electron barrier layer, and an undoped p-side intermediate layer disposed on or above the p-side composition graded layer. A lower end of the ridge is positioned at the p-side intermediate layer.

The disclosed technology relates to the development of a monolithic active electro-optical device. The electro-optical device may be fabricated using the so-called nanoridge aspect ratio trapping (ART) approach. In one aspect, the disclosed technology is directed to a monolithic integrated electro-optical device, which comprises a III-V-semiconductor-material ridge structure arranged on a Si-based support region. The ridge structure includes a first-conductivity-type bottom region arranged on the support region, a first-conductivity-type lower blocking layer arranged on the top surface and parts of the side surfaces of the bottom region and configured to block second-conductivity-type charge carriers, a not-intentionally-doped (NID) intermediate region arranged on the top and side surfaces of the lower blocking layer and containing a recombination region, a second-conductivity-type upper blocking layer arranged on the top and side surfaces of the intermediate region and configured to block first-conductivity-type charge carriers, and a second-conductivity-type top region arranged on the top and side surfaces of the upper blocking layer.

A method of manufacturing a semiconductor laser device includes: forming an n-type nitride semiconductor layer; forming a first layer comprising In.sub.aGa.sub.1-aN (0<a<1) above the n-type nitride semiconductor layer; forming a second layer and a third layer above the first layer; forming an active layer having a single quantum well structure or a multiple quantum well structure above the second layer and the third layer; and forming a p-type nitride semiconductor layer above the active layer.

A light emitting device includes a substrate, a buffer layer, a first active layer, and a plurality of mesa regions. A portion of the first active layer includes a first electrical polarity. The plurality of mesa regions includes at least a portion of the first active layer, a light emitting region on the portion of the first active layer, and a second active layer on the light emitting region. A portion of the second active layer includes a second electrical polarity. The light emitting region is configured to emit light which has a target wavelength between 200 nm to 300 nm. A thickness of the light emitting region is a multiple of the target wavelength, and a dimension of the light emitting region parallel to the substrate is smaller than 10 times the target wavelength, such that the emitted light is confined to fewer than 10 transverse modes.

A light emitting device includes a substrate, a buffer layer, a first active layer, and a plurality of mesa regions. A portion of the first active layer includes a first electrical polarity. The plurality of mesa regions includes at least a portion of the first active layer, a light emitting region on the portion of the first active layer, and a second active layer on the light emitting region. A portion of the second active layer includes a second electrical polarity. The light emitting region is configured to emit light which has a target wavelength between 200 nm to 300 nm. A thickness of the light emitting region is a multiple of the target wavelength, and a dimension of the light emitting region parallel to the substrate is smaller than 10 times the target wavelength, such that the emitted light is confined to fewer than 10 transverse modes.

Laser diodes are configured to suppress lasing of a first and higher order modes along a fast axis of an optical beam emitted by the laser diode. An optical cavity is defined by a p-side of the laser diode, an n-side of the laser diode, and an active region located between the p- and n-sides. The n-side has an n-waveguide layer forming at least a portion of a waveguide having a quantum well offset towards the p-side. According to some embodiments, double cladding layers out-couple higher order modes. According to other embodiments, double waveguides (e.g., symmetric and asymmetric) reduce gain applied to higher order modes.